1. to foam, foam up, froth, froth up (intransitive)

2. to lather (as of a horse) (intransitive)

3. to unfoam, remove foam from (transitive)

4. to take the scum off (transitive)

5. to skim (transitive)

6. to scour (shops, etc., looking for something) (figuratively)

7. to grift (to skim off profits etc.) (figuratively)